Percutaneous access to the cardiovascular system is used to diagnose, evaluate, and treat a variety of conditions. A typical procedure involves passing a wire guide through an opening in a patient's skin, often by way of an introducer sheath, which connects to a vascular structure such as a vein or artery. The wire guide can then be passed through the cardiovascular system to a location of interest within the patient. Once the wire guide has been appropriately positioned, a catheter may be passed into the patient and guided by the wire guide to a location where a procedure is to be performed. Angioplasty, imaging, and the placement of stents, grafts, filters and other devices, are common procedures which are performed according to variations of the above general technique. It is also common to use percutaneous access for the placement of catheters which deliver fluid at an intraluminal treatment site. Devices known as infusion catheters are used to deliver a therapeutic treatment fluid such as a thrombolytic agent to a clot or the like within a vein or artery.
A wide variety of infusion catheter designs are known and commercially available. One general class of infusion catheters utilizes a longitudinally extending lumen which connects a supply of therapeutic fluid located outside of the patient with an intraluminal space by way of ports communicating between the lumen and the intraluminal space. In such infusion catheters, the infusion fluid is typically delivered from infusion ports placed in proximity to the area to be treated. Since a distribution of the infusion ports in the catheter may often be different from the length of the treatment area, designs have been proposed in which a clinician can adjust which of the infusion ports are presently available for infusing the fluid, such as covering some of the infusion ports with a sheath, or sliding the sheath to expose previously covered infusion ports. One such design is known from U.S. Pat. No. 6,575,932 to O'Brien et al. O'Brien proposes a multi-balloon local delivery device, which purportedly allows precise adjustment of an inter-balloon distance to permit controlled delivery of therapeutics to a discreet length of a hollow tubular organ wall. While O'Brien and other slide type infusion catheter designs may function adequately, sliding components of a catheter within a treatment area from a location outside of the patient can be cumbersome, and in some instances risks introducing contaminated parts of the device into the patient. In other words, a slidable sheath strategy can require a user to position a device within a patient, slide part of it out of the patient, and then potentially slide a non-sterile part back into the patient. Alternatively, the clinician might simply be prevented from proceeding in an optimum way.